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<p>该备忘单提供了帮助您使用 <a href="https://golang.org">Golang</a> 的基本语法和方法。</p>
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1</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#关闭-2">关闭 2</a><a aria-hidden="true" class="leve2 tocs-link" data-num="2" href="#golang-包packages">Golang 包(Packages)</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#导入">导入</a><a aria-hidden="true" class="leve4 tocs-link" data-num="4" href="#等同于">等同于</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#别名">别名</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#packages">Packages</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#导出名称">导出名称</a><a aria-hidden="true" class="leve2 tocs-link" data-num="2" href="#golang-并发">Golang 并发</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#协程">协程</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#waitgroup">WaitGroup</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#closing-channels">Closing channels</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#缓冲通道">缓冲通道</a><a aria-hidden="true" class="leve2 tocs-link" data-num="2" href="#golang-错误控制">Golang 错误控制</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#延迟函数">延迟函数</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#lambda-defer">Lambda defer</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#defer">Defer</a><a aria-hidden="true" class="leve2 tocs-link" data-num="2" href="#golang-方法methods">Golang 方法(Methods)</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#接收器">接收器</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#mutation">Mutation</a><a aria-hidden="true" class="leve2 tocs-link" data-num="2" href="#golang-接口interfaces">Golang 接口(Interfaces)</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#基本接口interfaces">基本接口(Interfaces)</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#结构struct">结构(Struct)</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#方法methods">方法(Methods)</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#接口实例">接口实例</a><a aria-hidden="true" class="leve2 tocs-link" data-num="2" href="#杂项">杂项</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#关键字keywords">关键字(Keywords)</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#运算符和标点符号">运算符和标点符号</a><a aria-hidden="true" class="leve2 tocs-link" data-num="2" href="#go-命令">Go 命令</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#go-编译器命令">Go 编译器命令</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#env">ENV</a><a aria-hidden="true" class="leve3 tocs-link" data-num="3" href="#module">Module</a><a aria-hidden="true" class="leve2 tocs-link" data-num="2" href="#另见">另见</a></div></div><div class="h1wrap-body"><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="入门"><a aria-hidden="true" tabindex="-1" href="#入门"><span class="icon icon-link"></span></a>入门</h2><div class="wrap-body">
</div></div><div class="h2wrap-body"><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="hellogo"><a aria-hidden="true" tabindex="-1" href="#hellogo"><span class="icon icon-link"></span></a>hello.go</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">package</span> main
</span><span class="code-line"><span class="token keyword">import</span> <span class="token string">"fmt"</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">    fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Hello, world!"</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p>直接运行</p>
<pre class="language-shell"><code class="language-shell code-highlight"><span class="code-line">$ go run hello.go
</span><span class="code-line">Hello, world<span class="token operator">!</span>
</span></code></pre>
<p>或者在 <a href="https://repl.it/languages/go">Go repl</a> 中尝试一，<code>go</code> 命令<a href="#go-%E5%91%BD%E4%BB%A4">参考</a></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="变量"><a aria-hidden="true" tabindex="-1" href="#变量"><span class="icon icon-link"></span></a>变量</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">var</span> s1 <span class="token builtin">string</span>
</span><span class="code-line">s1 <span class="token operator">=</span> <span class="token string">"Learn Go!"</span>
</span><span class="code-line"><span class="token comment">// 一次声明多个变量</span>
</span><span class="code-line"><span class="token keyword">var</span> b<span class="token punctuation">,</span> c <span class="token builtin">int</span> <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span>
</span><span class="code-line"><span class="token keyword">var</span> d <span class="token operator">=</span> <span class="token boolean">true</span>
</span></code></pre>
<p>简短声明</p>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">s1 <span class="token operator">:=</span> <span class="token string">"Learn Go!"</span>        <span class="token comment">// string</span>
</span><span class="code-line">b<span class="token punctuation">,</span> c <span class="token operator">:=</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span>             <span class="token comment">// int</span>
</span><span class="code-line">d <span class="token operator">:=</span> <span class="token boolean">true</span>                <span class="token comment">// bool</span>
</span></code></pre>
<p>参见：<a href="#golang-%E5%9F%BA%E6%9C%AC%E7%B1%BB%E5%9E%8B">基本类型</a></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="函数"><a aria-hidden="true" tabindex="-1" href="#函数"><span class="icon icon-link"></span></a>函数</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">package</span> main
</span><span class="code-line"><span class="token keyword">import</span> <span class="token string">"fmt"</span>
</span><span class="code-line"><span class="token comment">// 程序的入口点</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Hello world!"</span><span class="token punctuation">)</span>
</span><span class="code-line">  <span class="token function">say</span><span class="token punctuation">(</span><span class="token string">"Hello Go!"</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">say</span><span class="token punctuation">(</span>message <span class="token builtin">string</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"You said: "</span><span class="token punctuation">,</span> message<span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p>参见：<a href="#golang-%E5%87%BD%E6%95%B0">函数(Functions)</a></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="注释"><a aria-hidden="true" tabindex="-1" href="#注释"><span class="icon icon-link"></span></a>注释</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token comment">// 单行注释</span>
</span><span class="code-line"><span class="token comment">/* 这是
</span></span><span class="code-line"><span class="token comment">多行注释 */</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="如果语句"><a aria-hidden="true" tabindex="-1" href="#如果语句"><span class="icon icon-link"></span></a>如果语句</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">if</span> <span class="token boolean">true</span> <span class="token punctuation">{</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Yes!"</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p>参见：<a href="#golang-%E6%9D%A1%E4%BB%B6%E6%8E%A7%E5%88%B6">条件控制</a></p>
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="golang-基本类型"><a aria-hidden="true" tabindex="-1" href="#golang-基本类型"><span class="icon icon-link"></span></a>Golang 基本类型</h2><div class="wrap-body">
</div></div><div class="h2wrap-body"><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="字符串-strings"><a aria-hidden="true" tabindex="-1" href="#字符串-strings"><span class="icon icon-link"></span></a>字符串 Strings</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">s1 <span class="token operator">:=</span> <span class="token string">"Hello"</span> <span class="token operator">+</span> <span class="token string">"World"</span>
</span><span class="code-line">s2 <span class="token operator">:=</span> <span class="token string">`A "raw" string literal
</span></span><span class="code-line"><span class="token string">can include line breaks.`</span>
</span><span class="code-line"><span class="token comment">// 输出：10</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token function">len</span><span class="token punctuation">(</span>s1<span class="token punctuation">)</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token comment">// 输出：Hello</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token function">string</span><span class="token punctuation">(</span>s1<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">:</span><span class="token number">5</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
</span></code></pre>
<p>字符串的类型为 <code>字符串</code></p>
</div></div></div><div class="wrap h3body-exist"><div class="wrap-header h3wrap"><h3 id="数字-numbers"><a aria-hidden="true" tabindex="-1" href="#数字-numbers"><span class="icon icon-link"></span></a>数字 Numbers</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">num <span class="token operator">:=</span> <span class="token number">3</span>             <span class="token comment">// int</span>
</span><span class="code-line">num <span class="token operator">:=</span> <span class="token number">3.</span>            <span class="token comment">// float64</span>
</span><span class="code-line">num <span class="token operator">:=</span> <span class="token number">3</span> <span class="token operator">+</span> <span class="token number">4i</span>        <span class="token comment">// complex128</span>
</span><span class="code-line">num <span class="token operator">:=</span> <span class="token function">byte</span><span class="token punctuation">(</span><span class="token char">'a'</span><span class="token punctuation">)</span>     <span class="token comment">// byte (alias: uint8)</span>
</span><span class="code-line"><span class="token keyword">var</span> u <span class="token builtin">uint</span> <span class="token operator">=</span> <span class="token number">7</span>       <span class="token comment">// uint (unsigned)</span>
</span><span class="code-line"><span class="token keyword">var</span> p <span class="token builtin">float32</span> <span class="token operator">=</span> <span class="token number">22.7</span>  <span class="token comment">// 32-bit float</span>
</span></code></pre>
<h4 id="操作符-operators"><a aria-hidden="true" tabindex="-1" href="#操作符-operators"><span class="icon icon-link"></span></a>操作符 Operators</h4>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">x <span class="token operator">:=</span> <span class="token number">5</span>
</span><span class="code-line">x<span class="token operator">++</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"x + 4 ="</span><span class="token punctuation">,</span> x <span class="token operator">+</span> <span class="token number">4</span><span class="token punctuation">)</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"x * 4 ="</span><span class="token punctuation">,</span> x <span class="token operator">*</span> <span class="token number">4</span><span class="token punctuation">)</span> 
</span></code></pre>
<p>参见：<a href="#%E8%BF%90%E7%AE%97%E7%AC%A6%E5%92%8C%E6%A0%87%E7%82%B9%E7%AC%A6%E5%8F%B7">更多操作符</a></p>
</div></div></div><div class="wrap h3body-exist"><div class="wrap-header h3wrap"><h3 id="布尔值-booleans"><a aria-hidden="true" tabindex="-1" href="#布尔值-booleans"><span class="icon icon-link"></span></a>布尔值 Booleans</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">isTrue   <span class="token operator">:=</span> <span class="token boolean">true</span>
</span><span class="code-line">isFalse  <span class="token operator">:=</span> <span class="token boolean">false</span>
</span></code></pre>
<h4 id="操作符"><a aria-hidden="true" tabindex="-1" href="#操作符"><span class="icon icon-link"></span></a>操作符</h4>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token boolean">true</span> <span class="token operator">&#x26;&#x26;</span> <span class="token boolean">true</span><span class="token punctuation">)</span>   <span class="token comment">// true </span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token boolean">true</span> <span class="token operator">&#x26;&#x26;</span> <span class="token boolean">false</span><span class="token punctuation">)</span>  <span class="token comment">// false</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token boolean">true</span> <span class="token operator">||</span> <span class="token boolean">true</span><span class="token punctuation">)</span>   <span class="token comment">// true</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token boolean">true</span> <span class="token operator">||</span> <span class="token boolean">false</span><span class="token punctuation">)</span>  <span class="token comment">// true</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token operator">!</span><span class="token boolean">true</span><span class="token punctuation">)</span>          <span class="token comment">// false</span>
</span></code></pre>
<p>参见：<a href="#%E8%BF%90%E7%AE%97%E7%AC%A6%E5%92%8C%E6%A0%87%E7%82%B9%E7%AC%A6%E5%8F%B7">更多操作符</a></p>
</div></div></div><div class="wrap h3body-exist row-span-2"><div class="wrap-header h3wrap"><h3 id="数组-arrays"><a aria-hidden="true" tabindex="-1" href="#数组-arrays"><span class="icon icon-link"></span></a>数组 Arrays</h3><div class="wrap-body">
<!--rehype:wrap-class=row-span-2-->
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">┌────┬────┬────┬────┬─────┬─────┐
</span><span class="code-line"><span class="token operator">|</span> <span class="token number">2</span>  <span class="token operator">|</span> <span class="token number">3</span>  <span class="token operator">|</span> <span class="token number">5</span>  <span class="token operator">|</span> <span class="token number">7</span>  <span class="token operator">|</span> <span class="token number">11</span>  <span class="token operator">|</span> <span class="token number">13</span>  <span class="token operator">|</span>
</span><span class="code-line">└────┴────┴────┴────┴─────┴─────┘
</span><span class="code-line">  <span class="token number">0</span>    <span class="token number">1</span>    <span class="token number">2</span>    <span class="token number">3</span>     <span class="token number">4</span>     <span class="token number">5</span>
</span></code></pre>
<hr>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">primes <span class="token operator">:=</span> <span class="token punctuation">[</span><span class="token operator">...</span><span class="token punctuation">]</span><span class="token builtin">int</span><span class="token punctuation">{</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">5</span><span class="token punctuation">,</span> <span class="token number">7</span><span class="token punctuation">,</span> <span class="token number">11</span><span class="token punctuation">,</span> <span class="token number">13</span><span class="token punctuation">}</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token function">len</span><span class="token punctuation">(</span>primes<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token comment">// => 6</span>
</span><span class="code-line"><span class="token comment">// 输出：[2 3 5 7 11 13]</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>primes<span class="token punctuation">)</span>
</span><span class="code-line"><span class="token comment">// 与 [:3] 相同，输出：[2 3 5]</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>primes<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">:</span><span class="token number">3</span><span class="token punctuation">]</span><span class="token punctuation">)</span>
</span></code></pre>
<hr>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">var</span> a <span class="token punctuation">[</span><span class="token number">2</span><span class="token punctuation">]</span><span class="token builtin">string</span>
</span><span class="code-line">a<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token string">"Hello"</span>
</span><span class="code-line">a<span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token string">"World"</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>a<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">,</span> a<span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">)</span> <span class="token comment">//=> Hello World</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>a<span class="token punctuation">)</span>   <span class="token comment">// => [Hello World]</span>
</span></code></pre>
<h4 id="2d-array"><a aria-hidden="true" tabindex="-1" href="#2d-array"><span class="icon icon-link"></span></a>2d array</h4>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">var</span> twoDimension <span class="token punctuation">[</span><span class="token number">2</span><span class="token punctuation">]</span><span class="token punctuation">[</span><span class="token number">3</span><span class="token punctuation">]</span><span class="token builtin">int</span>
</span><span class="code-line"><span class="token keyword">for</span> i <span class="token operator">:=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator">&#x3C;</span> <span class="token number">2</span><span class="token punctuation">;</span> i<span class="token operator">++</span> <span class="token punctuation">{</span>
</span><span class="code-line">    <span class="token keyword">for</span> j <span class="token operator">:=</span> <span class="token number">0</span><span class="token punctuation">;</span> j <span class="token operator">&#x3C;</span> <span class="token number">3</span><span class="token punctuation">;</span> j<span class="token operator">++</span> <span class="token punctuation">{</span>
</span><span class="code-line">        twoDimension<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">[</span>j<span class="token punctuation">]</span> <span class="token operator">=</span> i <span class="token operator">+</span> j
</span><span class="code-line">    <span class="token punctuation">}</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token comment">// => 2d:  [[0 1 2] [1 2 3]]</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"2d: "</span><span class="token punctuation">,</span> twoDimension<span class="token punctuation">)</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="指针pointers"><a aria-hidden="true" tabindex="-1" href="#指针pointers"><span class="icon icon-link"></span></a>指针(Pointers)</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> main <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  b <span class="token operator">:=</span> <span class="token operator">*</span><span class="token function">getPointer</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Value is"</span><span class="token punctuation">,</span> b<span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line">
</span><span class="code-line"><span class="token keyword">func</span> getPointer <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">(</span>myPointer <span class="token operator">*</span><span class="token builtin">int</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  a <span class="token operator">:=</span> <span class="token number">234</span>
</span><span class="code-line">  <span class="token keyword">return</span> <span class="token operator">&#x26;</span>a
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line">
</span><span class="code-line">a <span class="token operator">:=</span> <span class="token function">new</span><span class="token punctuation">(</span><span class="token builtin">int</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token operator">*</span>a <span class="token operator">=</span> <span class="token number">234</span>
</span></code></pre>
<p>参见：<a href="https://tour.golang.org/moretypes/1">指针(Pointers)</a></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="切片slices"><a aria-hidden="true" tabindex="-1" href="#切片slices"><span class="icon icon-link"></span></a>切片(Slices)</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">s <span class="token operator">:=</span> <span class="token function">make</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token builtin">string</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">)</span>
</span><span class="code-line">s<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token string">"a"</span>
</span><span class="code-line">s<span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token string">"b"</span>
</span><span class="code-line">s <span class="token operator">=</span> <span class="token function">append</span><span class="token punctuation">(</span>s<span class="token punctuation">,</span> <span class="token string">"d"</span><span class="token punctuation">)</span>
</span><span class="code-line">s <span class="token operator">=</span> <span class="token function">append</span><span class="token punctuation">(</span>s<span class="token punctuation">,</span> <span class="token string">"e"</span><span class="token punctuation">,</span> <span class="token string">"f"</span><span class="token punctuation">)</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>s<span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">)</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token function">len</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span><span class="token punctuation">)</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>s<span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">:</span><span class="token number">3</span><span class="token punctuation">]</span><span class="token punctuation">)</span>
</span><span class="code-line">slice <span class="token operator">:=</span> <span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token builtin">int</span><span class="token punctuation">{</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">4</span><span class="token punctuation">}</span>
</span></code></pre>
<p>另见：<a href="https://gobyexample.com/slices">切片示例</a></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="常量constants"><a aria-hidden="true" tabindex="-1" href="#常量constants"><span class="icon icon-link"></span></a>常量(Constants)</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">const</span> s <span class="token builtin">string</span> <span class="token operator">=</span> <span class="token string">"constant"</span>
</span><span class="code-line"><span class="token keyword">const</span> Phi <span class="token operator">=</span> <span class="token number">1.618</span>
</span><span class="code-line"><span class="token keyword">const</span> n <span class="token operator">=</span> <span class="token number">500000000</span>
</span><span class="code-line"><span class="token keyword">const</span> d <span class="token operator">=</span> <span class="token number">3e20</span> <span class="token operator">/</span> n
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>d<span class="token punctuation">)</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-exist"><div class="wrap-header h3wrap"><h3 id="类型转换"><a aria-hidden="true" tabindex="-1" href="#类型转换"><span class="icon icon-link"></span></a>类型转换</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">i <span class="token operator">:=</span> <span class="token number">90</span>
</span><span class="code-line">f <span class="token operator">:=</span> <span class="token function">float64</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span>
</span><span class="code-line">u <span class="token operator">:=</span> <span class="token function">uint</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span>
</span><span class="code-line"><span class="token comment">// 将等于字符Z</span>
</span><span class="code-line">s <span class="token operator">:=</span> <span class="token function">string</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span>
</span></code></pre>
<h4 id="如何获取int字符串"><a aria-hidden="true" tabindex="-1" href="#如何获取int字符串"><span class="icon icon-link"></span></a>如何获取int字符串？</h4>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">i <span class="token operator">:=</span> <span class="token number">90</span>
</span><span class="code-line"><span class="token comment">// 需要导入“strconv”</span>
</span><span class="code-line">s <span class="token operator">:=</span> strconv<span class="token punctuation">.</span><span class="token function">Itoa</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span> <span class="token comment">// Outputs: 90</span>
</span></code></pre>
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="golang-字符串"><a aria-hidden="true" tabindex="-1" href="#golang-字符串"><span class="icon icon-link"></span></a>Golang 字符串</h2><div class="wrap-body">
</div></div><div class="h2wrap-body"><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="字符串函数"><a aria-hidden="true" tabindex="-1" href="#字符串函数"><span class="icon icon-link"></span></a>字符串函数</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">package</span> main
</span><span class="code-line"><span class="token keyword">import</span> <span class="token punctuation">(</span>
</span><span class="code-line">        <span class="token string">"fmt"</span>
</span><span class="code-line">        s <span class="token string">"strings"</span>
</span><span class="code-line"><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">    <span class="token comment">/* 需要将字符串导入为 s */</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>s<span class="token punctuation">.</span><span class="token function">Contains</span><span class="token punctuation">(</span><span class="token string">"test"</span><span class="token punctuation">,</span> <span class="token string">"e"</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
</span><span class="code-line">    <span class="token comment">/* 内置 */</span>
</span><span class="code-line">    fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token function">len</span><span class="token punctuation">(</span><span class="token string">"hello"</span><span class="token punctuation">)</span><span class="token punctuation">)</span>  <span class="token comment">// => 5</span>
</span><span class="code-line">    <span class="token comment">// 输出: 101</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"hello"</span><span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">)</span>
</span><span class="code-line">    <span class="token comment">// 输出: e</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token function">string</span><span class="token punctuation">(</span><span class="token string">"hello"</span><span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist row-span-2 col-span-2"><div class="wrap-header h3wrap"><h3 id="fmtprintf"><a aria-hidden="true" tabindex="-1" href="#fmtprintf"><span class="icon icon-link"></span></a>fmt.Printf</h3><div class="wrap-body">
<!--rehype:wrap-class=row-span-2 col-span-2-->
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">package</span> main
</span><span class="code-line"><span class="token keyword">import</span> <span class="token punctuation">(</span>
</span><span class="code-line">        <span class="token string">"fmt"</span>
</span><span class="code-line">        <span class="token string">"os"</span>
</span><span class="code-line"><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token keyword">type</span> point <span class="token keyword">struct</span> <span class="token punctuation">{</span>
</span><span class="code-line">        x<span class="token punctuation">,</span> y <span class="token builtin">int</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">        p <span class="token operator">:=</span> point<span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">}</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%v\n"</span><span class="token punctuation">,</span> p<span class="token punctuation">)</span>                        <span class="token comment">// => {1 2}</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%+v\n"</span><span class="token punctuation">,</span> p<span class="token punctuation">)</span>                       <span class="token comment">// => {x:1 y:2}</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%#v\n"</span><span class="token punctuation">,</span> p<span class="token punctuation">)</span>                       <span class="token comment">// => main.point{x:1, y:2}</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%T\n"</span><span class="token punctuation">,</span> p<span class="token punctuation">)</span>                        <span class="token comment">// => main.point</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%t\n"</span><span class="token punctuation">,</span> <span class="token boolean">true</span><span class="token punctuation">)</span>                     <span class="token comment">// => TRUE</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%d\n"</span><span class="token punctuation">,</span> <span class="token number">123</span><span class="token punctuation">)</span>                      <span class="token comment">// => 123</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%b\n"</span><span class="token punctuation">,</span> <span class="token number">14</span><span class="token punctuation">)</span>                       <span class="token comment">// => 1110</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%c\n"</span><span class="token punctuation">,</span> <span class="token number">33</span><span class="token punctuation">)</span>                       <span class="token comment">// => !</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%x\n"</span><span class="token punctuation">,</span> <span class="token number">456</span><span class="token punctuation">)</span>                      <span class="token comment">// => 1c8</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%f\n"</span><span class="token punctuation">,</span> <span class="token number">78.9</span><span class="token punctuation">)</span>                     <span class="token comment">// => 78.9</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%e\n"</span><span class="token punctuation">,</span> <span class="token number">123400000.0</span><span class="token punctuation">)</span>              <span class="token comment">// => 1.23E+08</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%E\n"</span><span class="token punctuation">,</span> <span class="token number">123400000.0</span><span class="token punctuation">)</span>              <span class="token comment">// => 1.23E+08</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%s\n"</span><span class="token punctuation">,</span> <span class="token string">"\"string\""</span><span class="token punctuation">)</span>             <span class="token comment">// => "string"</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%q\n"</span><span class="token punctuation">,</span> <span class="token string">"\"string\""</span><span class="token punctuation">)</span>             <span class="token comment">// => "\"string\""</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%x\n"</span><span class="token punctuation">,</span> <span class="token string">"hex this"</span><span class="token punctuation">)</span>               <span class="token comment">// => 6.86578E+15</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%p\n"</span><span class="token punctuation">,</span> <span class="token operator">&#x26;</span>p<span class="token punctuation">)</span>                       <span class="token comment">// => 0xc00002c040</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"|%6d|%6d|\n"</span><span class="token punctuation">,</span> <span class="token number">12</span><span class="token punctuation">,</span> <span class="token number">345</span><span class="token punctuation">)</span>           <span class="token comment">// => |    12|   345|</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"|%6.2f|%6.2f|\n"</span><span class="token punctuation">,</span> <span class="token number">1.2</span><span class="token punctuation">,</span> <span class="token number">3.45</span><span class="token punctuation">)</span>     <span class="token comment">// => |  1.20|  3.45|</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"|%-6.2f|%-6.2f|\n"</span><span class="token punctuation">,</span> <span class="token number">1.2</span><span class="token punctuation">,</span> <span class="token number">3.45</span><span class="token punctuation">)</span>   <span class="token comment">// => |1.20  |3.45  |</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"|%6s|%6s|\n"</span><span class="token punctuation">,</span> <span class="token string">"foo"</span><span class="token punctuation">,</span> <span class="token string">"b"</span><span class="token punctuation">)</span>        <span class="token comment">// => |   foo|     b|</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"|%-6s|%-6s|\n"</span><span class="token punctuation">,</span> <span class="token string">"foo"</span><span class="token punctuation">,</span> <span class="token string">"b"</span><span class="token punctuation">)</span>      <span class="token comment">// => |foo   |b     |</span>
</span><span class="code-line">        s <span class="token operator">:=</span> fmt<span class="token punctuation">.</span><span class="token function">Sprintf</span><span class="token punctuation">(</span><span class="token string">"a %s"</span><span class="token punctuation">,</span> <span class="token string">"string"</span><span class="token punctuation">)</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Fprintf</span><span class="token punctuation">(</span>os<span class="token punctuation">.</span>Stderr<span class="token punctuation">,</span> <span class="token string">"an %s\n"</span><span class="token punctuation">,</span> <span class="token string">"error"</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p>另见：<a href="https://golang.org/pkg/fmt/">fmt</a></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="函数实例"><a aria-hidden="true" tabindex="-1" href="#函数实例"><span class="icon icon-link"></span></a>函数实例</h3><div class="wrap-body">

























































<table><thead><tr><th>实例</th><th>Result</th></tr></thead><tbody><tr><td>Contains("test", "es")</td><td>true</td></tr><tr><td>Count("test", "t")</td><td>2</td></tr><tr><td>HasPrefix("test", "te")</td><td>true</td></tr><tr><td>HasSuffix("test", "st")</td><td>true</td></tr><tr><td>Index("test", "e")</td><td>1</td></tr><tr><td>Join([]string{"a", "b"}, "-")</td><td>a-b</td></tr><tr><td>Repeat("a", 5)</td><td>aaaaa</td></tr><tr><td>Replace("foo", "o", "0", -1)</td><td>f00</td></tr><tr><td>Replace("foo", "o", "0", 1)</td><td>f0o</td></tr><tr><td>Split("a-b-c-d-e", "-")</td><td>[a b c d e]</td></tr><tr><td>ToLower("TEST")</td><td>test</td></tr><tr><td>ToUpper("test")</td><td>TEST</td></tr></tbody></table>
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="golang-条件控制"><a aria-hidden="true" tabindex="-1" href="#golang-条件控制"><span class="icon icon-link"></span></a>Golang 条件控制</h2><div class="wrap-body">
</div></div><div class="h2wrap-body"><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="有条件的"><a aria-hidden="true" tabindex="-1" href="#有条件的"><span class="icon icon-link"></span></a>有条件的</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">a <span class="token operator">:=</span> <span class="token number">10</span>
</span><span class="code-line"><span class="token keyword">if</span> a <span class="token operator">></span> <span class="token number">20</span> <span class="token punctuation">{</span>
</span><span class="code-line">    fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">">"</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token keyword">if</span> a <span class="token operator">&#x3C;</span> <span class="token number">20</span> <span class="token punctuation">{</span>
</span><span class="code-line">    fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"&#x3C;"</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
</span><span class="code-line">    fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"="</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="if-中的语句"><a aria-hidden="true" tabindex="-1" href="#if-中的语句"><span class="icon icon-link"></span></a>if 中的语句</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">x <span class="token operator">:=</span> <span class="token string">"hello go!"</span>
</span><span class="code-line"><span class="token keyword">if</span> count <span class="token operator">:=</span> <span class="token function">len</span><span class="token punctuation">(</span>x<span class="token punctuation">)</span><span class="token punctuation">;</span> count <span class="token operator">></span> <span class="token number">0</span> <span class="token punctuation">{</span>
</span><span class="code-line">    fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Yes"</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<hr>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">if</span> <span class="token boolean">_</span><span class="token punctuation">,</span> err <span class="token operator">:=</span> <span class="token function">doThing</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> err <span class="token operator">!=</span> <span class="token boolean">nil</span> <span class="token punctuation">{</span>
</span><span class="code-line">    fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Uh oh"</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="switch"><a aria-hidden="true" tabindex="-1" href="#switch"><span class="icon icon-link"></span></a>Switch</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">x <span class="token operator">:=</span> <span class="token number">42.0</span>
</span><span class="code-line"><span class="token keyword">switch</span> x <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token keyword">case</span> <span class="token number">0</span><span class="token punctuation">:</span>
</span><span class="code-line">  <span class="token keyword">case</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">:</span>
</span><span class="code-line">      fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Multiple matches"</span><span class="token punctuation">)</span>
</span><span class="code-line">  <span class="token keyword">case</span> <span class="token number">42</span><span class="token punctuation">:</span>   <span class="token comment">// Don't "fall through".</span>
</span><span class="code-line">      fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"reached"</span><span class="token punctuation">)</span>
</span><span class="code-line">  <span class="token keyword">case</span> <span class="token number">43</span><span class="token punctuation">:</span>
</span><span class="code-line">      fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Unreached"</span><span class="token punctuation">)</span>
</span><span class="code-line">  <span class="token keyword">default</span><span class="token punctuation">:</span>
</span><span class="code-line">      fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Optional"</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p>参见：<a href="https://github.com/golang/go/wiki/Switch">Switch</a></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="for-loop"><a aria-hidden="true" tabindex="-1" href="#for-loop"><span class="icon icon-link"></span></a>For loop</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">for</span> i <span class="token operator">:=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator">&#x3C;=</span> <span class="token number">10</span><span class="token punctuation">;</span> i<span class="token operator">++</span> <span class="token punctuation">{</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"i: "</span><span class="token punctuation">,</span> i<span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="对于-range-循环"><a aria-hidden="true" tabindex="-1" href="#对于-range-循环"><span class="icon icon-link"></span></a>对于 Range 循环</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">nums <span class="token operator">:=</span> <span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token builtin">int</span><span class="token punctuation">{</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">4</span><span class="token punctuation">}</span>
</span><span class="code-line">sum <span class="token operator">:=</span> <span class="token number">0</span>
</span><span class="code-line"><span class="token keyword">for</span> <span class="token boolean">_</span><span class="token punctuation">,</span> num <span class="token operator">:=</span> <span class="token keyword">range</span> nums <span class="token punctuation">{</span>
</span><span class="code-line">  sum <span class="token operator">+=</span> num
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"sum:"</span><span class="token punctuation">,</span> sum<span class="token punctuation">)</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="for-循环"><a aria-hidden="true" tabindex="-1" href="#for-循环"><span class="icon icon-link"></span></a>For 循环</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">i <span class="token operator">:=</span> <span class="token number">1</span>
</span><span class="code-line"><span class="token keyword">for</span> i <span class="token operator">&#x3C;=</span> <span class="token number">3</span> <span class="token punctuation">{</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span>
</span><span class="code-line">  i<span class="token operator">++</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="continue-关键字"><a aria-hidden="true" tabindex="-1" href="#continue-关键字"><span class="icon icon-link"></span></a>Continue 关键字</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">for</span> i <span class="token operator">:=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator">&#x3C;=</span> <span class="token number">5</span><span class="token punctuation">;</span> i<span class="token operator">++</span> <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token keyword">if</span> i <span class="token operator">%</span> <span class="token number">2</span> <span class="token operator">==</span> <span class="token number">0</span> <span class="token punctuation">{</span>
</span><span class="code-line">      <span class="token keyword">continue</span>
</span><span class="code-line">  <span class="token punctuation">}</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="break-关键字"><a aria-hidden="true" tabindex="-1" href="#break-关键字"><span class="icon icon-link"></span></a>Break 关键字</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">for</span> <span class="token punctuation">{</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"loop"</span><span class="token punctuation">)</span>
</span><span class="code-line">  <span class="token keyword">break</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="golang-结构和映射"><a aria-hidden="true" tabindex="-1" href="#golang-结构和映射"><span class="icon icon-link"></span></a>Golang 结构和映射</h2><div class="wrap-body">
</div></div><div class="h2wrap-body"><div class="wrap h3body-not-exist row-span-2"><div class="wrap-header h3wrap"><h3 id="定义"><a aria-hidden="true" tabindex="-1" href="#定义"><span class="icon icon-link"></span></a>定义</h3><div class="wrap-body">
<!--rehype:wrap-class=row-span-2-->
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">package</span> main
</span><span class="code-line"><span class="token keyword">import</span> <span class="token punctuation">(</span>
</span><span class="code-line">        <span class="token string">"fmt"</span>
</span><span class="code-line"><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token keyword">type</span> Vertex <span class="token keyword">struct</span> <span class="token punctuation">{</span>
</span><span class="code-line">        X <span class="token builtin">int</span>
</span><span class="code-line">        Y <span class="token builtin">int</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">        v <span class="token operator">:=</span> Vertex<span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">}</span>
</span><span class="code-line">        v<span class="token punctuation">.</span>X <span class="token operator">=</span> <span class="token number">4</span>
</span><span class="code-line">        fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>v<span class="token punctuation">.</span>X<span class="token punctuation">,</span> v<span class="token punctuation">.</span>Y<span class="token punctuation">)</span> <span class="token comment">// => 4 2</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p>参见：<a href="https://tour.golang.org/moretypes/2">结构(Structs)</a></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="字面量"><a aria-hidden="true" tabindex="-1" href="#字面量"><span class="icon icon-link"></span></a>字面量</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">v <span class="token operator">:=</span> Vertex<span class="token punctuation">{</span>X<span class="token punctuation">:</span> <span class="token number">1</span><span class="token punctuation">,</span> Y<span class="token punctuation">:</span> <span class="token number">2</span><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token comment">// Field names can be omitted</span>
</span><span class="code-line">v <span class="token operator">:=</span> Vertex<span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token comment">// Y is implicit</span>
</span><span class="code-line">v <span class="token operator">:=</span> Vertex<span class="token punctuation">{</span>X<span class="token punctuation">:</span> <span class="token number">1</span><span class="token punctuation">}</span>
</span></code></pre>
<p>您还可以输入字段名</p>
</div></div></div><div class="wrap h3body-not-exist row-span-2"><div class="wrap-header h3wrap"><h3 id="映射"><a aria-hidden="true" tabindex="-1" href="#映射"><span class="icon icon-link"></span></a>映射</h3><div class="wrap-body">
<!--rehype:wrap-class=row-span-2-->
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">m <span class="token operator">:=</span> <span class="token function">make</span><span class="token punctuation">(</span><span class="token keyword">map</span><span class="token punctuation">[</span><span class="token builtin">string</span><span class="token punctuation">]</span><span class="token builtin">int</span><span class="token punctuation">)</span>
</span><span class="code-line">m<span class="token punctuation">[</span><span class="token string">"k1"</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token number">7</span>
</span><span class="code-line">m<span class="token punctuation">[</span><span class="token string">"k2"</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token number">13</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>m<span class="token punctuation">)</span> <span class="token comment">// => map[k1:7 k2:13]</span>
</span><span class="code-line">v1 <span class="token operator">:=</span> m<span class="token punctuation">[</span><span class="token string">"k1"</span><span class="token punctuation">]</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>v1<span class="token punctuation">)</span>     <span class="token comment">// => 7</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token function">len</span><span class="token punctuation">(</span>m<span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token comment">// => 2</span>
</span><span class="code-line"><span class="token function">delete</span><span class="token punctuation">(</span>m<span class="token punctuation">,</span> <span class="token string">"k2"</span><span class="token punctuation">)</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>m<span class="token punctuation">)</span> <span class="token comment">// => map[k1:7]</span>
</span><span class="code-line"><span class="token boolean">_</span><span class="token punctuation">,</span> prs <span class="token operator">:=</span> m<span class="token punctuation">[</span><span class="token string">"k2"</span><span class="token punctuation">]</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>prs<span class="token punctuation">)</span> <span class="token comment">// => false</span>
</span><span class="code-line">n <span class="token operator">:=</span> <span class="token keyword">map</span><span class="token punctuation">[</span><span class="token builtin">string</span><span class="token punctuation">]</span><span class="token builtin">int</span><span class="token punctuation">{</span><span class="token string">"foo"</span><span class="token punctuation">:</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token string">"bar"</span><span class="token punctuation">:</span> <span class="token number">2</span><span class="token punctuation">}</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>n<span class="token punctuation">)</span> <span class="token comment">// => map[bar:2 foo:1]</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="指向结构的指针"><a aria-hidden="true" tabindex="-1" href="#指向结构的指针"><span class="icon icon-link"></span></a>指向结构的指针</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">v <span class="token operator">:=</span> <span class="token operator">&#x26;</span>Vertex<span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">}</span>
</span><span class="code-line">v<span class="token punctuation">.</span>X <span class="token operator">=</span> <span class="token number">2</span>
</span></code></pre>
<p>Doing <code>v.X</code> is the same as doing <code>(*v).X</code>, when <code>v</code> is a pointer.</p>
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="golang-函数"><a aria-hidden="true" tabindex="-1" href="#golang-函数"><span class="icon icon-link"></span></a>Golang 函数</h2><div class="wrap-body">
</div></div><div class="h2wrap-body"><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="多个参数"><a aria-hidden="true" tabindex="-1" href="#多个参数"><span class="icon icon-link"></span></a>多个参数</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token function">plus</span><span class="token punctuation">(</span>a <span class="token builtin">int</span><span class="token punctuation">,</span> b <span class="token builtin">int</span><span class="token punctuation">)</span> <span class="token builtin">int</span> <span class="token punctuation">{</span>
</span><span class="code-line">    <span class="token keyword">return</span> a <span class="token operator">+</span> b
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">plusPlus</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> b<span class="token punctuation">,</span> c <span class="token builtin">int</span><span class="token punctuation">)</span> <span class="token builtin">int</span> <span class="token punctuation">{</span>
</span><span class="code-line">    <span class="token keyword">return</span> a <span class="token operator">+</span> b <span class="token operator">+</span> c
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token function">plus</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token function">plusPlus</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="多次返回"><a aria-hidden="true" tabindex="-1" href="#多次返回"><span class="icon icon-link"></span></a>多次返回</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token function">vals</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">(</span><span class="token builtin">int</span><span class="token punctuation">,</span> <span class="token builtin">int</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token keyword">return</span> <span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">7</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line">a<span class="token punctuation">,</span> b <span class="token operator">:=</span> <span class="token function">vals</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>a<span class="token punctuation">)</span>    <span class="token comment">// => 3</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>b<span class="token punctuation">)</span>    <span class="token comment">// => 7</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="匿名函数"><a aria-hidden="true" tabindex="-1" href="#匿名函数"><span class="icon icon-link"></span></a>匿名函数</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">r1<span class="token punctuation">,</span> r2 <span class="token operator">:=</span> <span class="token keyword">func</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">(</span><span class="token builtin">string</span><span class="token punctuation">,</span> <span class="token builtin">string</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">    x <span class="token operator">:=</span> <span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token builtin">string</span><span class="token punctuation">{</span><span class="token string">"hello"</span><span class="token punctuation">,</span> <span class="token string">"world"</span><span class="token punctuation">}</span>
</span><span class="code-line">    <span class="token keyword">return</span> x<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">,</span> x<span class="token punctuation">[</span><span class="token number">1</span><span class="token punctuation">]</span>
</span><span class="code-line"><span class="token punctuation">}</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token comment">// => hello world</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>r1<span class="token punctuation">,</span> r2<span class="token punctuation">)</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="命名返回"><a aria-hidden="true" tabindex="-1" href="#命名返回"><span class="icon icon-link"></span></a>命名返回</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token function">split</span><span class="token punctuation">(</span>sum <span class="token builtin">int</span><span class="token punctuation">)</span> <span class="token punctuation">(</span>x<span class="token punctuation">,</span> y <span class="token builtin">int</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  x <span class="token operator">=</span> sum <span class="token operator">*</span> <span class="token number">4</span> <span class="token operator">/</span> <span class="token number">9</span>
</span><span class="code-line">  y <span class="token operator">=</span> sum <span class="token operator">-</span> x
</span><span class="code-line">  <span class="token keyword">return</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line">x<span class="token punctuation">,</span> y <span class="token operator">:=</span> <span class="token function">split</span><span class="token punctuation">(</span><span class="token number">17</span><span class="token punctuation">)</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>x<span class="token punctuation">)</span>   <span class="token comment">// => 7</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>y<span class="token punctuation">)</span>   <span class="token comment">// => 10</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="变量函数"><a aria-hidden="true" tabindex="-1" href="#变量函数"><span class="icon icon-link"></span></a>变量函数</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token function">sum</span><span class="token punctuation">(</span>nums <span class="token operator">...</span><span class="token builtin">int</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Print</span><span class="token punctuation">(</span>nums<span class="token punctuation">,</span> <span class="token string">" "</span><span class="token punctuation">)</span>
</span><span class="code-line">  total <span class="token operator">:=</span> <span class="token number">0</span>
</span><span class="code-line">  <span class="token keyword">for</span> <span class="token boolean">_</span><span class="token punctuation">,</span> num <span class="token operator">:=</span> <span class="token keyword">range</span> nums <span class="token punctuation">{</span>
</span><span class="code-line">      total <span class="token operator">+=</span> num
</span><span class="code-line">  <span class="token punctuation">}</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>total<span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token function">sum</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">)</span>     <span class="token comment">//=> [1 2] 3</span>
</span><span class="code-line"><span class="token function">sum</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">)</span>  <span class="token comment">// => [1 2 3] 6</span>
</span><span class="code-line">nums <span class="token operator">:=</span> <span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token builtin">int</span><span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">4</span><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token function">sum</span><span class="token punctuation">(</span>nums<span class="token operator">...</span><span class="token punctuation">)</span>  <span class="token comment">// => [1 2 3 4] 10</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="初始化函数"><a aria-hidden="true" tabindex="-1" href="#初始化函数"><span class="icon icon-link"></span></a>初始化函数</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">import</span> <span class="token operator">--</span><span class="token operator">></span> <span class="token keyword">const</span> <span class="token operator">--</span><span class="token operator">></span> <span class="token keyword">var</span> <span class="token operator">--</span><span class="token operator">></span> <span class="token function">init</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span></code></pre>
<hr>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">var</span> num <span class="token operator">=</span> <span class="token function">setNumber</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">setNumber</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token builtin">int</span> <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token keyword">return</span> <span class="token number">42</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">init</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  num <span class="token operator">=</span> <span class="token number">0</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>num<span class="token punctuation">)</span> <span class="token comment">// => 0</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="作为值的函数"><a aria-hidden="true" tabindex="-1" href="#作为值的函数"><span class="icon icon-link"></span></a>作为值的函数</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token comment">// 将函数赋给名称</span>
</span><span class="code-line">  add <span class="token operator">:=</span> <span class="token keyword">func</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> b <span class="token builtin">int</span><span class="token punctuation">)</span> <span class="token builtin">int</span> <span class="token punctuation">{</span>
</span><span class="code-line">      <span class="token keyword">return</span> a <span class="token operator">+</span> b
</span><span class="code-line">  <span class="token punctuation">}</span>
</span><span class="code-line">  <span class="token comment">// 使用名称调用函数</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">4</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token comment">// => 7</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="关闭-1"><a aria-hidden="true" tabindex="-1" href="#关闭-1"><span class="icon icon-link"></span></a>关闭 1</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token function">scope</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">func</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token builtin">int</span><span class="token punctuation">{</span>
</span><span class="code-line">  outer_var <span class="token operator">:=</span> <span class="token number">2</span>
</span><span class="code-line">  foo <span class="token operator">:=</span> <span class="token keyword">func</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token builtin">int</span> <span class="token punctuation">{</span><span class="token keyword">return</span> outer_var<span class="token punctuation">}</span>
</span><span class="code-line">  <span class="token keyword">return</span> foo
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token comment">// Outpus: 2</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token function">scope</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="关闭-2"><a aria-hidden="true" tabindex="-1" href="#关闭-2"><span class="icon icon-link"></span></a>关闭 2</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token function">outer</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">(</span><span class="token keyword">func</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token builtin">int</span><span class="token punctuation">,</span> <span class="token builtin">int</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">    outer_var <span class="token operator">:=</span> <span class="token number">2</span>
</span><span class="code-line">    inner <span class="token operator">:=</span> <span class="token keyword">func</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token builtin">int</span> <span class="token punctuation">{</span>
</span><span class="code-line">        outer_var <span class="token operator">+=</span> <span class="token number">99</span>
</span><span class="code-line">        <span class="token keyword">return</span> outer_var
</span><span class="code-line">    <span class="token punctuation">}</span>
</span><span class="code-line">    <span class="token function">inner</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span><span class="code-line">    <span class="token keyword">return</span> inner<span class="token punctuation">,</span> outer_var
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line">inner<span class="token punctuation">,</span> val <span class="token operator">:=</span> <span class="token function">outer</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token function">inner</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span> <span class="token comment">// => 200</span>
</span><span class="code-line">fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>val<span class="token punctuation">)</span>     <span class="token comment">// => 101</span>
</span></code></pre>
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="golang-包packages"><a aria-hidden="true" tabindex="-1" href="#golang-包packages"><span class="icon icon-link"></span></a>Golang 包(Packages)</h2><div class="wrap-body">
</div></div><div class="h2wrap-body"><div class="wrap h3body-exist row-span-2"><div class="wrap-header h3wrap"><h3 id="导入"><a aria-hidden="true" tabindex="-1" href="#导入"><span class="icon icon-link"></span></a>导入</h3><div class="wrap-body">
<!--rehype:wrap-class=row-span-2-->
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">import</span> <span class="token string">"fmt"</span>
</span><span class="code-line"><span class="token keyword">import</span> <span class="token string">"math/rand"</span>
</span></code></pre>
<h4 id="等同于"><a aria-hidden="true" tabindex="-1" href="#等同于"><span class="icon icon-link"></span></a>等同于</h4>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">import</span> <span class="token punctuation">(</span>
</span><span class="code-line">  <span class="token string">"fmt"</span>        <span class="token comment">// 给 fmt.Println</span>
</span><span class="code-line">  <span class="token string">"math/rand"</span>  <span class="token comment">// 给 rand.Intn</span>
</span><span class="code-line"><span class="token punctuation">)</span>
</span></code></pre>
<p>另见：<a href="https://tour.golang.org/basics/1">导入</a></p>
</div></div></div><div class="wrap h3body-not-exist row-span-2"><div class="wrap-header h3wrap"><h3 id="别名"><a aria-hidden="true" tabindex="-1" href="#别名"><span class="icon icon-link"></span></a>别名</h3><div class="wrap-body">
<!--rehype:wrap-class=row-span-2-->
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">import</span> r <span class="token string">"math/rand"</span>
</span></code></pre>
<hr>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">import</span> <span class="token punctuation">(</span>
</span><span class="code-line">    <span class="token string">"fmt"</span>
</span><span class="code-line">    r <span class="token string">"math/rand"</span>
</span><span class="code-line"><span class="token punctuation">)</span>
</span></code></pre>
<hr>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">r<span class="token punctuation">.</span><span class="token function">Intn</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="packages"><a aria-hidden="true" tabindex="-1" href="#packages"><span class="icon icon-link"></span></a>Packages</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">package</span> main
</span><span class="code-line"><span class="token comment">// 一个内部包只能被另一个包导入</span>
</span><span class="code-line"><span class="token comment">// 那是在以内部目录的父级为根的树内</span>
</span><span class="code-line"><span class="token keyword">package</span> internal
</span></code></pre>
<p>另见：<a href="https://go.dev/doc/go1.4#internalpackages">内部包</a></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="导出名称"><a aria-hidden="true" tabindex="-1" href="#导出名称"><span class="icon icon-link"></span></a>导出名称</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token comment">// 以大写字母开头</span>
</span><span class="code-line"><span class="token keyword">func</span> Hello <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  ···
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p>另见：<a href="https://tour.golang.org/basics/3">导出的名称</a></p>
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="golang-并发"><a aria-hidden="true" tabindex="-1" href="#golang-并发"><span class="icon icon-link"></span></a>Golang 并发</h2><div class="wrap-body">
</div></div><div class="h2wrap-body"><div class="wrap h3body-not-exist row-span-2"><div class="wrap-header h3wrap"><h3 id="协程"><a aria-hidden="true" tabindex="-1" href="#协程"><span class="icon icon-link"></span></a>协程</h3><div class="wrap-body">
<!--rehype:wrap-class=row-span-2-->
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">package</span> main
</span><span class="code-line"><span class="token keyword">import</span> <span class="token punctuation">(</span>
</span><span class="code-line">    <span class="token string">"fmt"</span>
</span><span class="code-line">    <span class="token string">"time"</span>
</span><span class="code-line"><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">f</span><span class="token punctuation">(</span>from <span class="token builtin">string</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">    <span class="token keyword">for</span> i <span class="token operator">:=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator">&#x3C;</span> <span class="token number">3</span><span class="token punctuation">;</span> i<span class="token operator">++</span> <span class="token punctuation">{</span>
</span><span class="code-line">            fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>from<span class="token punctuation">,</span> <span class="token string">":"</span><span class="token punctuation">,</span> i<span class="token punctuation">)</span>
</span><span class="code-line">    <span class="token punctuation">}</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">    <span class="token function">f</span><span class="token punctuation">(</span><span class="token string">"direct"</span><span class="token punctuation">)</span>
</span><span class="code-line">    <span class="token keyword">go</span> <span class="token function">f</span><span class="token punctuation">(</span><span class="token string">"goroutine"</span><span class="token punctuation">)</span>
</span><span class="code-line">    <span class="token keyword">go</span> <span class="token keyword">func</span><span class="token punctuation">(</span>msg <span class="token builtin">string</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">            fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span>msg<span class="token punctuation">)</span>
</span><span class="code-line">    <span class="token punctuation">}</span><span class="token punctuation">(</span><span class="token string">"going"</span><span class="token punctuation">)</span>
</span><span class="code-line">    time<span class="token punctuation">.</span><span class="token function">Sleep</span><span class="token punctuation">(</span>time<span class="token punctuation">.</span>Second<span class="token punctuation">)</span>
</span><span class="code-line">    fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"done"</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p>参见：<a href="https://tour.golang.org/concurrency/1">Goroutines</a>, <a href="https://tour.golang.org/concurrency/2">Channels</a></p>
</div></div></div><div class="wrap h3body-not-exist row-span-2"><div class="wrap-header h3wrap"><h3 id="waitgroup"><a aria-hidden="true" tabindex="-1" href="#waitgroup"><span class="icon icon-link"></span></a>WaitGroup</h3><div class="wrap-body">
<!--rehype:wrap-class=row-span-2-->
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">package</span> main
</span><span class="code-line"><span class="token keyword">import</span> <span class="token punctuation">(</span>
</span><span class="code-line">    <span class="token string">"fmt"</span>
</span><span class="code-line">    <span class="token string">"sync"</span>
</span><span class="code-line">    <span class="token string">"time"</span>
</span><span class="code-line"><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">w</span><span class="token punctuation">(</span>id <span class="token builtin">int</span><span class="token punctuation">,</span> wg <span class="token operator">*</span>sync<span class="token punctuation">.</span>WaitGroup<span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">    <span class="token keyword">defer</span> wg<span class="token punctuation">.</span><span class="token function">Done</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span><span class="code-line">    fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%d starting\n"</span><span class="token punctuation">,</span> id<span class="token punctuation">)</span>
</span><span class="code-line">    time<span class="token punctuation">.</span><span class="token function">Sleep</span><span class="token punctuation">(</span>time<span class="token punctuation">.</span>Second<span class="token punctuation">)</span>
</span><span class="code-line">    fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"%d done\n"</span><span class="token punctuation">,</span> id<span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">    <span class="token keyword">var</span> wg sync<span class="token punctuation">.</span>WaitGroup
</span><span class="code-line">    <span class="token keyword">for</span> i <span class="token operator">:=</span> <span class="token number">1</span><span class="token punctuation">;</span> i <span class="token operator">&#x3C;=</span> <span class="token number">5</span><span class="token punctuation">;</span> i<span class="token operator">++</span> <span class="token punctuation">{</span>
</span><span class="code-line">            wg<span class="token punctuation">.</span><span class="token function">Add</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span>
</span><span class="code-line">            <span class="token keyword">go</span> <span class="token function">w</span><span class="token punctuation">(</span>i<span class="token punctuation">,</span> <span class="token operator">&#x26;</span>wg<span class="token punctuation">)</span>
</span><span class="code-line">    <span class="token punctuation">}</span>
</span><span class="code-line">    wg<span class="token punctuation">.</span><span class="token function">Wait</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p>参见：<a href="https://golang.org/pkg/sync/#WaitGroup">WaitGroup</a></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="closing-channels"><a aria-hidden="true" tabindex="-1" href="#closing-channels"><span class="icon icon-link"></span></a>Closing channels</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">ch <span class="token operator">&#x3C;-</span> <span class="token number">1</span>
</span><span class="code-line">ch <span class="token operator">&#x3C;-</span> <span class="token number">2</span>
</span><span class="code-line">ch <span class="token operator">&#x3C;-</span> <span class="token number">3</span>
</span><span class="code-line"><span class="token function">close</span><span class="token punctuation">(</span>ch<span class="token punctuation">)</span> <span class="token comment">// 关闭频道</span>
</span></code></pre>
<hr>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token comment">// 迭代通道直到关闭</span>
</span><span class="code-line"><span class="token keyword">for</span> i <span class="token operator">:=</span> <span class="token keyword">range</span> ch <span class="token punctuation">{</span>
</span><span class="code-line">  ···
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<hr>
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token comment">// Closed if `ok == false`</span>
</span><span class="code-line">v<span class="token punctuation">,</span> ok <span class="token operator">:=</span> <span class="token operator">&#x3C;-</span> ch
</span></code></pre>
<p>参见：<a href="https://tour.golang.org/concurrency/4">范围和关闭</a></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="缓冲通道"><a aria-hidden="true" tabindex="-1" href="#缓冲通道"><span class="icon icon-link"></span></a>缓冲通道</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line">ch <span class="token operator">:=</span> <span class="token function">make</span><span class="token punctuation">(</span><span class="token keyword">chan</span> <span class="token builtin">int</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">)</span>
</span><span class="code-line">ch <span class="token operator">&#x3C;-</span> <span class="token number">1</span>
</span><span class="code-line">ch <span class="token operator">&#x3C;-</span> <span class="token number">2</span>
</span><span class="code-line">ch <span class="token operator">&#x3C;-</span> <span class="token number">3</span>
</span><span class="code-line"><span class="token comment">// 致命错误：</span>
</span><span class="code-line"><span class="token comment">// 所有 goroutine 都处于休眠状态 - 死锁</span>
</span></code></pre>
<p>参见：<a href="https://tour.golang.org/concurrency/3">缓冲通道</a></p>
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="golang-错误控制"><a aria-hidden="true" tabindex="-1" href="#golang-错误控制"><span class="icon icon-link"></span></a>Golang 错误控制</h2><div class="wrap-body">
</div></div><div class="h2wrap-body"><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="延迟函数"><a aria-hidden="true" tabindex="-1" href="#延迟函数"><span class="icon icon-link"></span></a>延迟函数</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token keyword">defer</span> <span class="token keyword">func</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">    fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Done"</span><span class="token punctuation">)</span>
</span><span class="code-line">  <span class="token punctuation">}</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Working..."</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="lambda-defer"><a aria-hidden="true" tabindex="-1" href="#lambda-defer"><span class="icon icon-link"></span></a>Lambda defer</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token keyword">var</span> d <span class="token operator">=</span> <span class="token function">int64</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span>
</span><span class="code-line">  <span class="token keyword">defer</span> <span class="token keyword">func</span><span class="token punctuation">(</span>d <span class="token operator">*</span><span class="token builtin">int64</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">    fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"&#x26; %v Unix Sec\n"</span><span class="token punctuation">,</span> <span class="token operator">*</span>d<span class="token punctuation">)</span>
</span><span class="code-line">  <span class="token punctuation">}</span><span class="token punctuation">(</span><span class="token operator">&#x26;</span>d<span class="token punctuation">)</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Print</span><span class="token punctuation">(</span><span class="token string">"Done "</span><span class="token punctuation">)</span>
</span><span class="code-line">  d <span class="token operator">=</span> time<span class="token punctuation">.</span><span class="token function">Now</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">Unix</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p><code>defer</code> 函数使用当前值<code>d</code>，除非我们使用指针在 <code>main</code> 末尾获取最终值</p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="defer"><a aria-hidden="true" tabindex="-1" href="#defer"><span class="icon icon-link"></span></a>Defer</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token keyword">defer</span> fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Done"</span><span class="token punctuation">)</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Println</span><span class="token punctuation">(</span><span class="token string">"Working..."</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p>参见：<a href="https://blog.golang.org/defer-panic-and-recover">Defer, panic and recover</a></p>
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="golang-方法methods"><a aria-hidden="true" tabindex="-1" href="#golang-方法methods"><span class="icon icon-link"></span></a>Golang 方法(Methods)</h2><div class="wrap-body">
<!--rehype:body-class=cols-2-->
</div></div><div class="h2wrap-body cols-2"><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="接收器"><a aria-hidden="true" tabindex="-1" href="#接收器"><span class="icon icon-link"></span></a>接收器</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">type</span> Vertex <span class="token keyword">struct</span> <span class="token punctuation">{</span>
</span><span class="code-line">  X<span class="token punctuation">,</span> Y <span class="token builtin">float64</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line">
</span><span class="code-line"><span class="token keyword">func</span> <span class="token punctuation">(</span>v Vertex<span class="token punctuation">)</span> <span class="token function">Abs</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token builtin">float64</span> <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token keyword">return</span> math<span class="token punctuation">.</span><span class="token function">Sqrt</span><span class="token punctuation">(</span>v<span class="token punctuation">.</span>X <span class="token operator">*</span> v<span class="token punctuation">.</span>X <span class="token operator">+</span> v<span class="token punctuation">.</span>Y <span class="token operator">*</span> v<span class="token punctuation">.</span>Y<span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line">
</span><span class="code-line">v <span class="token operator">:=</span> Vertex<span class="token punctuation">{</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">}</span>
</span><span class="code-line">v<span class="token punctuation">.</span><span class="token function">Abs</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</span></code></pre>
<p>参见：<a href="https://tour.golang.org/methods/1">Methods</a></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="mutation"><a aria-hidden="true" tabindex="-1" href="#mutation"><span class="icon icon-link"></span></a>Mutation</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token punctuation">(</span>v <span class="token operator">*</span>Vertex<span class="token punctuation">)</span> <span class="token function">Scale</span><span class="token punctuation">(</span>f <span class="token builtin">float64</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  v<span class="token punctuation">.</span>X <span class="token operator">=</span> v<span class="token punctuation">.</span>X <span class="token operator">*</span> f
</span><span class="code-line">  v<span class="token punctuation">.</span>Y <span class="token operator">=</span> v<span class="token punctuation">.</span>Y <span class="token operator">*</span> f
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line">
</span><span class="code-line">v <span class="token operator">:=</span> Vertex<span class="token punctuation">{</span><span class="token number">6</span><span class="token punctuation">,</span> <span class="token number">12</span><span class="token punctuation">}</span>
</span><span class="code-line">v<span class="token punctuation">.</span><span class="token function">Scale</span><span class="token punctuation">(</span><span class="token number">0.5</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token comment">// `v` 已更新</span>
</span></code></pre>
<p>参见：<a href="https://tour.golang.org/methods/4">指针接收器</a></p>
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="golang-接口interfaces"><a aria-hidden="true" tabindex="-1" href="#golang-接口interfaces"><span class="icon icon-link"></span></a>Golang 接口(Interfaces)</h2><div class="wrap-body">
<!--rehype:body-class=cols-2-->
</div></div><div class="h2wrap-body cols-2"><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="基本接口interfaces"><a aria-hidden="true" tabindex="-1" href="#基本接口interfaces"><span class="icon icon-link"></span></a>基本接口(Interfaces)</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">type</span> Shape <span class="token keyword">interface</span> <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token function">Area</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token builtin">float64</span>
</span><span class="code-line">  <span class="token function">Perimeter</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token builtin">float64</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="结构struct"><a aria-hidden="true" tabindex="-1" href="#结构struct"><span class="icon icon-link"></span></a>结构(Struct)</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">type</span> Rectangle <span class="token keyword">struct</span> <span class="token punctuation">{</span>
</span><span class="code-line">  Length<span class="token punctuation">,</span> Width <span class="token builtin">float64</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p>结构 <code>Rectangle</code> 通过实现其所有方法隐式实现接口 <code>Shape</code></p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="方法methods"><a aria-hidden="true" tabindex="-1" href="#方法methods"><span class="icon icon-link"></span></a>方法(Methods)</h3><div class="wrap-body">
<pre class="language-go"><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token punctuation">(</span>r Rectangle<span class="token punctuation">)</span> <span class="token function">Area</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token builtin">float64</span> <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token keyword">return</span> r<span class="token punctuation">.</span>Length <span class="token operator">*</span> r<span class="token punctuation">.</span>Width
</span><span class="code-line"><span class="token punctuation">}</span>
</span><span class="code-line"><span class="token keyword">func</span> <span class="token punctuation">(</span>r Rectangle<span class="token punctuation">)</span> <span class="token function">Perimeter</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token builtin">float64</span> <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token keyword">return</span> <span class="token number">2</span> <span class="token operator">*</span> <span class="token punctuation">(</span>r<span class="token punctuation">.</span>Length <span class="token operator">+</span> r<span class="token punctuation">.</span>Width<span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<p>在 <code>Shape</code> 中定义的方法在<code>Rectangle</code>中实现</p>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="接口实例"><a aria-hidden="true" tabindex="-1" href="#接口实例"><span class="icon icon-link"></span></a>接口实例</h3><div class="wrap-body">
<pre class="wrap-text "><code class="language-go code-highlight"><span class="code-line"><span class="token keyword">func</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
</span><span class="code-line">  <span class="token keyword">var</span> r Shape <span class="token operator">=</span> Rectangle<span class="token punctuation">{</span>Length<span class="token punctuation">:</span> <span class="token number">3</span><span class="token punctuation">,</span> Width<span class="token punctuation">:</span> <span class="token number">4</span><span class="token punctuation">}</span>
</span><span class="code-line">  fmt<span class="token punctuation">.</span><span class="token function">Printf</span><span class="token punctuation">(</span><span class="token string">"Type of r: %T, Area: %v, Perimeter: %v."</span><span class="token punctuation">,</span> r<span class="token punctuation">,</span> r<span class="token punctuation">.</span><span class="token function">Area</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> r<span class="token punctuation">.</span><span class="token function">Perimeter</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
</span><span class="code-line"><span class="token punctuation">}</span>
</span></code></pre>
<!--rehype:className=wrap-text -->
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="杂项"><a aria-hidden="true" tabindex="-1" href="#杂项"><span class="icon icon-link"></span></a>杂项</h2><div class="wrap-body">
</div></div><div class="h2wrap-body"><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="关键字keywords"><a aria-hidden="true" tabindex="-1" href="#关键字keywords"><span class="icon icon-link"></span></a>关键字(Keywords)</h3><div class="wrap-body">
<ul class="cols-3 style-none">
<li>break</li>
<li>default</li>
<li>func</li>
<li>interface</li>
<li>select</li>
<li>case</li>
<li>defer</li>
<li>go</li>
<li>map</li>
<li>struct</li>
<li>chan</li>
<li>else</li>
<li>goto</li>
<li>package</li>
<li>switch</li>
<li>const</li>
<li>fallthrough</li>
<li>if</li>
<li>range</li>
<li>type</li>
<li>continue</li>
<li>for</li>
<li>import</li>
<li>return</li>
<li>var</li>
</ul>
<!--rehype:className=cols-3 style-none-->
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="运算符和标点符号"><a aria-hidden="true" tabindex="-1" href="#运算符和标点符号"><span class="icon icon-link"></span></a>运算符和标点符号</h3><div class="wrap-body">


















































































<table><thead><tr><th></th><th></th><th></th><th></th><th></th><th></th><th></th><th></th><th></th></tr></thead><tbody><tr><td><code>+</code></td><td><code>&#x26;</code></td><td><code>+=</code></td><td><code>&#x26;=</code></td><td><code>&#x26;&#x26;</code></td><td><code>==</code></td><td><code>!=</code></td><td><code>(</code></td><td><code>)</code></td></tr><tr><td><code>-</code></td><td><code>|</code></td><td><code>-=</code></td><td><code>|=</code></td><td><code>||</code></td><td><code>&#x3C;</code></td><td><code>&#x3C;=</code></td><td><code>[</code></td><td><code>]</code></td></tr><tr><td><code>*</code></td><td><code>^</code></td><td><code>*=</code></td><td><code>^=</code></td><td><code>&#x3C;-</code></td><td><code>></code></td><td><code>>=</code></td><td><code>{</code></td><td><code>}</code></td></tr><tr><td><code>/</code></td><td><code>&#x3C;&#x3C;</code></td><td><code>/=</code></td><td><code>&#x3C;&#x3C;=</code></td><td><code>++</code></td><td><code>=</code></td><td><code>:=</code></td><td><code>,</code></td><td><code>;</code></td></tr><tr><td><code>%</code></td><td><code>>></code></td><td><code>%=</code></td><td><code>>>=</code></td><td><code>--</code></td><td><code>!</code></td><td><code>...</code></td><td><code>.</code></td><td><code>:</code></td></tr><tr><td></td><td><code>&#x26;^</code></td><td><code>&#x26;^=</code></td><td></td><td></td><td></td><td></td><td></td><td></td></tr></tbody></table>
</div></div></div></div></div><div class="wrap h2body-exist"><div class="wrap-header h2wrap"><h2 id="go-命令"><a aria-hidden="true" tabindex="-1" href="#go-命令"><span class="icon icon-link"></span></a>Go 命令</h2><div class="wrap-body">
</div></div><div class="h2wrap-body"><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="go-编译器命令"><a aria-hidden="true" tabindex="-1" href="#go-编译器命令"><span class="icon icon-link"></span></a>Go 编译器命令</h3><div class="wrap-body">













































































<table><thead><tr><th align="left">:-</th><th>--</th></tr></thead><tbody><tr><td align="left"><code>go command [参数]</code></td><td>go 命令 [参数]</td></tr><tr><td align="left"><code>go build</code></td><td>编译包和依赖包</td></tr><tr><td align="left"><code>go clean</code></td><td>移除对象和缓存文件</td></tr><tr><td align="left"><code>go doc</code></td><td>显示包的文档</td></tr><tr><td align="left"><code>go env</code></td><td>打印go的环境变量信息</td></tr><tr><td align="left"><code>go bug</code></td><td>报告bug</td></tr><tr><td align="left"><code>go fix</code></td><td>更新包使用新的api</td></tr><tr><td align="left"><code>go fmt</code></td><td>格式规范化代码</td></tr><tr><td align="left"><code>go generate</code></td><td>通过处理资源生成go文件</td></tr><tr><td align="left"><code>go get</code></td><td>下载并安装包及其依赖</td></tr><tr><td align="left"><code>go install</code></td><td>编译和安装包及其依赖</td></tr><tr><td align="left"><code>go list</code></td><td>列出所有包</td></tr><tr><td align="left"><code>go run</code></td><td>编译和运行go程序</td></tr><tr><td align="left"><code>go test</code></td><td>测试</td></tr><tr><td align="left"><code>go tool</code></td><td>运行给定的go工具</td></tr><tr><td align="left"><code>go version</code></td><td>显示go当前版本</td></tr><tr><td align="left"><code>go vet</code></td><td>发现代码中可能的错误</td></tr></tbody></table>
</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="env"><a aria-hidden="true" tabindex="-1" href="#env"><span class="icon icon-link"></span></a>ENV</h3><div class="wrap-body">





























<table class="style-list-arrow"><thead><tr><th align="left">:-</th><th>--</th></tr></thead><tbody><tr><td align="left"><code>GOOS</code></td><td>编译系统</td></tr><tr><td align="left"><code>GOARCH</code></td><td>编译arch</td></tr><tr><td align="left"><code>GO111MODULE</code></td><td>gomod开关</td></tr><tr><td align="left"><code>GOPROXY</code></td><td>go代理 <a href="https://goproxy.io">https://goproxy.io</a>  <a href="https://goproxy.cn">https://goproxy.cn</a></td></tr><tr><td align="left"><code>GOSSAFUNC</code></td><td>生成 <code>SSA.html</code> 文件，展示代码优化的每一步 <code>GOSSAFUNC=func_name go build</code></td></tr></tbody></table>
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</div></div></div><div class="wrap h3body-not-exist"><div class="wrap-header h3wrap"><h3 id="module"><a aria-hidden="true" tabindex="-1" href="#module"><span class="icon icon-link"></span></a>Module</h3><div class="wrap-body">

































<table class="style-list-arrow"><thead><tr><th align="left">:-</th><th>--</th></tr></thead><tbody><tr><td align="left"><code>go mod init</code></td><td>初始化当前文件夹，创建go.mod文件</td></tr><tr><td align="left"><code>go mod download</code></td><td>下载依赖的module到本地</td></tr><tr><td align="left"><code>go mod tidy</code></td><td>增加缺少的module，删除无用的module</td></tr><tr><td align="left"><code>go mod vendor</code></td><td>将依赖复制到vendor下</td></tr><tr><td align="left">文件 <code>go.mod</code></td><td>依赖列表和版本约束</td></tr><tr><td align="left">文件 <code>go.sum</code></td><td>记录 <code>module</code> 文件 <code>hash</code> 值，用于安全校验</td></tr></tbody></table>
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</div></div></div></div></div><div class="wrap h2body-not-exist"><div class="wrap-header h2wrap"><h2 id="另见"><a aria-hidden="true" tabindex="-1" href="#另见"><span class="icon icon-link"></span></a>另见</h2><div class="wrap-body">
<ul>
<li><a href="https://devhints.io/go">Devhints</a> <em>(devhints.io)</em></li>
<li><a href="https://tour.golang.org/welcome/1">A tour of Go</a> <em>(tour.golang.org)</em></li>
<li><a href="https://github.com/golang/go/wiki/">Golang wiki</a> <em>(github.com)</em></li>
<li><a href="https://golang.org/doc/effective_go.html">Effective Go</a> <em>(golang.org)</em></li>
<li><a href="https://gobyexample.com/">Go by Example</a> <em>(gobyexample.com)</em></li>
<li><a href="https://awesome-go.com/">Awesome Go</a> <em>(awesome-go.com)</em></li>
<li><a href="https://www.youtube.com/channel/UC_BzFbxG2za3bp5NRRRXJSw">JustForFunc Youtube</a> <em>(youtube.com)</em></li>
<li><a href="https://github.com/golang/go/wiki/CodeReviewComments">Style Guide</a> <em>(github.com)</em></li>
</ul>
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